


Beasts

by Gang_of_Shadow



Series: Setleth Stories [1]
Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Angst, Angst and Fluff and Smut, Desk Sex, F/M, Fluff, Idiots in Love, Monster sex kind of?, Nabataen Shape Shifting, Porn, Porn With Plot, Porn with Feelings, Post-Timeskip | War Phase (Fire Emblem: Three Houses), Sex, Shapeshifting
Language: English
Status: Completed
Published: 2020-12-22
Updated: 2020-12-22
Packaged: 2021-03-11 00:00:56
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 11,151
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28235832
Author URL: https://archiveofourown.org/users/Gang_of_Shadow/pseuds/Gang_of_Shadow
Summary: When Seteth disappears from the monastery Byleth goes in search of him. When she finds him she's met with far more than she was expecting...___One of my stories for Seteth's Birthday Bash 2020 (they're all Setleth cause I love them)#SetethBBNSFW
Relationships: My Unit | Byleth & Seteth, My Unit | Byleth/Seteth, Setleth - Relationship
Series: Setleth Stories [1]
Series URL: https://archiveofourown.org/series/2068416
Comments: 10
Kudos: 63
Collections: Seteth Birthday Bash 2020





	Beasts

**Author's Note:**

> I love Seteth, I love Setleth so here you gooooooo!
> 
> This ones for the Day 1 prompt for Seteth's Birthday Bash 2020 which was Nabatean/Fatigue.  
> https://twitter.com/setethbday2020

Byleth hadn't seen Seteth all day and she was beginning to worry. It was unlike him to be unavailable for any extended length of time, certainly not without letting someone know in advance. Hanneman, Manuela, Catherine and Shamir all had no idea where he could be. The guard at the gates of the monastery had not seen him leave.

Her chest tightened as she tried to run through the possibilities in her mind, recall what might have happened to send him away. Something she might have mentioned. Something she may have missed…

She could not say that they were close, though not for her lack of trying. Seteth had always been so bound to his duties to the church, to Rhea, the knights, and Flayn that Byleth doubted he had time for anyone or anything else in his life. She didn't want to be a nuisance or a distraction just because she felt a one-sided attraction to him.

She knew he was a good man. Perhaps a bit cold and rigid, but good, and she wouldn't change him for anything. Besides since she'd woken from her five-year slumber he had thawed somewhat.

Prior to her fall into the chasm that had opened the day Garreg Mach fell, he had treated her almost like a volatile substance - something to be kept at a distance and handled with caution. He wasn't fond of many of her methods, or the risks she took, but he still seemed to acknowledge her ability and skill. It wasn't until her father died that he seemed to realize she was more than a mercenary or a weapon at the church’s disposal. And then again, when she aided him and Flayn on the Rhodos coast she noticed another slight shift. He had even shared the truth of who Flayn really was to him that day…

And yet the closeness she yearned for always seemed to be out of reach. She'd made efforts to ease his workload, build his confidence and trust in her. At some point she had found herself wanting to be more than just another member of the church to him, though she was not certain when it had happened. Perhaps it had been when he apologised for doubting her. Or how he'd trusted her with Flayn's safety and his most precious secret.

He'd said they were like family… And he already treated her more like a friend of late, even like a sister, but never someone he'd consider to be…

She shook her head, fighting off feelings that would only serve as a distraction. He was missing and she needed to find him. How could she face Flayn if something had happened to him and she had remained idle?

After searching the offices and his personal quarters she started for the cathedral, but as she reached the bridge, she heard a sound erupt from the ravine below. It was strange, a cry halfway between beast and man, and she instantly froze in her tracks partway across the bridge. There were a few priests passing by on their way to the afternoon's service who paused and peered over the bridge. They looked perplexed but the sound was so far off that it was likely of no danger, so they continued on.

Byleth however, had a strange sinking feeling come over as she looked down into the valley below. Something in her chest tugged her downward to seek out the source of that wretched sound. Without wasting any more time, she ran to the stables and found his wyvern still in her stall but looking agitated.

Byleth had no natural talent with animals. She did well enough with horses, but wyverns had always seemed to have an instinctual dislike of her. That was until Seteth had decided to take the time to teach her how to care for them, and eventually ride them. She still didn't trust herself riding one into battle, but she felt confident enough simply travelling on the back of one.

But would his wyvern take her? She could take another, but Seteth and his wyvern had been together for years. She was certain the old girl would be able to help her find him, if she would be willing to carry her.

Approaching the stall slowly, Byleth held her hand out to the great black beast. She looked flustered but she leaned in to bump her snout into Byleth's palm and huffed at her. "He's disappeared, old girl." Byleth sighed, giving her nose a scratch. "Will you take me to find him?"

The wyvern nudged her hand over to where her reigns were hanging up on the wall of her stall by way of an answer. Byleth wasted no time, saddling her up and strapping her in. They were off in a matter of moments, diving into the ravine.

Byleth's heart raced as they swept through the area for what felt like eons. The longer they hovered above the area with no sign and no sound, the more tense she felt. But perhaps she was overreacting. Unexpected things happen, even to Seteth. He may have simply gone for a walk and forgot to let anyone know. He'd been quite stressed as they drew ever nearer to facing the Agarthans for what they all preyed would be the last time. Surely, this would all be for nothing and when she returned, he'd be standing there in the stables, arms crossed over his chest in disappointment.

Just when she thought she'd convinced herself she was just being foolish another horrible roar erupted from the wooded area just below them. The wyvern roared in answer before it dove for the source without her even having to spur her on. At the last minute she was able to reign her in, just before they crashed through the canopy. She scanned the area for a reasonable place to land, spying a small clearing and bringing them down.

The black beast wanted to follow her, unsatisfied with remaining in the clearing to wait. "You have to stay, girl. You're too big to make it through. I'll bring him home, I promise." She gave the wyvern a quick scratch under her chin before turning in the direction of the sound she'd heard.

She did not have to walk far before she came across a trail of broken branches and crushed foliage, along with pieces of discarded clothing - Seteth's cloak, then his shirt, a boot. Each item was in worse shape than the last, torn or ripped. She gathered them up under her arm and continued on, trying not to let her imagination get carried away as she tried to figure out what had taken place here.

When she heard rustling just a few meters ahead of her she slowed her pace, taking her sword from its sheath and crouching down low. She crept forward and strained to hear what it was ahead of her. She could hear breathing - panting, and a strangled noise. It didn't sound like a fight. It sounded like a wounded beast. Pressing on she came through the brush and found what she was looking for.

Seteth was hunched over on his hands and knees, facing away from her. He was breathing heavily. A sheen of sweat coated the bare skin of his back, his hair was a tussled mess. She'd never seen him in such a state before in her life, and it was such a shock that she staggered back. Her foot caught on a branch, giving her away and his head shot up, instantly snapping around to look at her.

The face that stared back at her was Seteth's but he had changed. Horns were protruding from his temples, his teeth had elongated and sharpened to points. When she looked down to his hands and feet, she saw sharp pointed claws. Emerald green scales had formed on his hands and arms, along his jaw and the ridge of his cheekbones.

His eyes remained the same as they ever were, and they looked out at her with such pain and shame that she forgot her fear and started forward.

"STAY AWAY!" It was a roar in every sense of the word, and she froze in her tracks. "Don't… Don't come near me." He spun away from her and started moving further into the forest.

"Seteth wait!" She ran forward and caught up to him in no time. His movements were slow, as though he were in pain. The way his body quaked and shuddered she thought he must be.

"I said stay back," he grunted, but he paused as she came up before him once again.

"Seteth what is going on? What is happening to you?" She couldn't keep the tremor from her voice as she spoke.

Seteth let out a strangled gasp as the horns at his temples grew before her eyes, curling back and around his ears. "It is my other form…" he hissed out.

"But you said you couldn't -"

"I know. I never expected… I can't control it for some reason. You should stay away. All of you."

"But -"

"I don't know if I can still control it…"

"I'm not leaving," she said flatly.

"You - it's dangerous, Byleth. Please…"

"You should not be alone. What if someone or _something_ comes upon you while you're like this?" she insisted.

He whirled on her, moving faster than she had expected and grabbed her roughly by the shoulders before she could react. His hold was so tight she knew immediately that she would bruise but she didn't flinch. "It's not safe, Byleth."

"I can handle myself,” she said, even has his claws bit into her flesh. "I'm waiting with you until this passes."

"It may never pass," Seteth spat bitterly before releasing her.

"It will. You have too much to lose… and you're too stubborn," she said flatly. The Seteth she knew would never leave Flayn behind. Not for anything.

He huffed out a sigh and pulled away from her again, just as another spasm wracked his frame. "This isn't like with Rhea, Byleth. It just started happening…"

She was silent a moment, thinking back on the events that had transpired before now. The fall of Garreg Mach, then Rhea transforming again at Shambalah to save them all from the Javelins of Light. Could being present for her transformations into the Immaculate One have triggered something in him. Would it trigger something in her eventually as well?

"You can conquer this, Seteth. You have one of the strongest wills I've ever known." She spoke softly now. Being combative now wouldn't help things. He needed to know he was not alone.

A chuckle burst out of him suddenly and she almost jumped out of her skin. "The only will stronger than mine is yours, I fear."

"Then I guess you're stuck with me for now." She ventured a smile and was rewarded with a toothy grin from Seteth. Bolstered by this she dared to move a few paces closer to him and dropped down to her knees on the mossy forest floor.

"I thank you for - for wanting to aid me, but there is little that can be done. This needs to run its course," he said, shifting to a seated position.

"I can wait."

"If anything happens to you -"

"I told you I can handle myself."

"I'd never forgive myself…"

"Then you'd best sort yourself out, hadn't you?"

"I told you, its not that simple. There is a - a condition that affects my people, _our_ people. It happens sometimes when one lives for so long. A madness starts to take hold. I think Rhea may be succumbing to it… Perhaps its been happening for some time and I just didn't notice. But I fear this is -"

"You're not mad, Seteth," she said quietly.

"Rhea did not seam mad either, but she's done things… Things I would never have condoned had I been aware of them. It's made me… question many things I thought to be true. I did not think this was possible for instance." His body still strained against itself. Every so often a limb would tense or twitch. He would shudder and wince until whatever it was had passed. Though he seemed more in control than when she'd found him, more scales had appeared on his skin since then. They ran down his spine between two raised and inflamed ridges that were protruding from his shoulder blades.

Suddenly he lurched forward, looking as though he might bolt. Without even thinking about it, Byleth lunged as well, dropping her sword and catching him around the waist. Whether it was instinct or not, he thrashed in her grasp, attempting to shake her loose.

"Be still, Seteth. Please… I won't harm you."

"But I might harm _you_ ," he grit out between his teeth as he shuddered in her arms. But he did become still… for a moment.

The calm was soon broken by his cries of pain. The ridges on his back split open as two great wings forced their way out of his body and unfolded to block what little sun was trickling through the canopy of leaves above them. His arms came around her, crushing her against him as he braced himself against the pain his new limbs brought with them.

She tensed as she felt his talons snag on the fabric of her shirt, tearing the cloth and then her skin. She yelped this time as sharp points bit into her flesh, but he didn’t seem to notice, too distracted by his own pain to maintain control. Byleth had seen and felt worse, far worse. She could withstand this now, for him…

She felt his hands flex on her back as he seemed to realize what had happened. His face was buried in her neck, his breath hot against her skin. For a moment she thought she felt his teeth graze the flesh at the crook of her neck, but he never broke the skin. "Leave me, Byleth. I can't…"

"Did you not tell me that we are like family? That you would never abandon me?"

A strangled noise rumbled forth from him. "It was _you_ who pointed out that promises like that are hard to keep."

"Giving up so easily then?" It came out as a rather pitiful whisper. She hated how she sounded - weak and scared - but her heart was on the verge breaking. Perhaps she was a fool to think she could do anything to help him, that she would be enough…

"Please, Byleth. I don't want to hurt you anymore," he pleaded, yet as he spoke his hold on her tightened.

She tried to soothe him, rubbing slow circles into his back as she spoke. "It's a small price to pay to ensure you stay with us, and that you're not alone right now."

"You -"

"Shhh… Just focus on my voice for a little while. I know I am not as skilled in story telling as you are, but I shall try my best to provide some distraction." She continued to trace soft spirals into his back and spoke softly as she told him every tale she knew.

Some of them were fables and fairy tales that she was certain he was already familiar with. Others were tales of her own life, of her father. Despite the short time she'd had with Jeralt, they had seen much, gotten into and out of so much trouble over the years. She surprised herself at the plethora of stories she could weave just from her own strange, mercenary life.

As she spoke Seteth eventually began to relax. His breathing became even, and the spasms that wracked his frame slowly became fewer before they eventually stopped all together. At some point she was able to draw them back so she could rest against the trunk of a tree while she continued to spin her tales.

She wasn't sure how long she rambled on, but by the time she started to drift to sleep the light coming through the trees nearly gone. She watched him as her eyelids started to droop. Without her noticing, he had fallen asleep, his head still pillowed on her shoulder. She took in his partially transformed features once again. If it hadn't been tainted by the pain it had caused him, she would have thought him beautiful. But then she'd already thought he was quite remarkable for some time.

As sleep took its hold, she wondered if this changed anything between them. Surely, he must know why she'd come - why she stayed. To her, her feelings had always been so obvious, and yet he'd never even seemed to notice…

Darkness started to push these thoughts aside and sleep pulled her down into the dark. But for a few brief moments she was able to be somewhat content to just have him in her arms.

* * *

It was dark when he woke with a start, half naked in the middle of the forest. There was someone in his arms, sleeping soundly, and the realization made his heart skip a beat. Looking down he found Byleth nestled against his chest, fast asleep. Seteth froze instantly, panic swelling, tightening in his ribcage. The events of the past day rapidly flooded his mind, followed immediately by shame and horror.

He shifted her carefully in his arms as if she were made of glass, checking the areas where his claws had sunk in. The marks on her arms didn't seem that bad, but the slashes down her back were deep and would likely scar. A pit formed in his stomach. An empty, yawning chasm filled with despair.

Why hadn't she just left him?

But didn't he already know? The way she behaved around him… She was always checking in on him when he worked late, taking on extra responsibilities so that he would have time to spend with Flayn, or just to relax. Byleth had taken to asking for his thoughts on strategy prior to each mission or what to prioritise around the monastery with regards to the many repairs that were needed.

He'd been critical of what he'd initially deemed carelessness on her part when she first arrived. But he soon realized that was far from the case. She took risks but they were calculated, and she had the skill to back up the risks she took. Her father was the blade breaker after all, and he'd trained her well. Her mercenary background had seemed like an odd fit for a teacher, but she took to it quickly and markedly well.

He saw how she was with not just her students but with Flayn. Kind and attentive, often nurturing, but she did not stray away from discipline when the situation called for it.

When he had learned what Rhea had done with Sitri everything suddenly felt tainted. Though he had no knowledge of it until after Byleth and Jeralt arrived, he still felt as though he were a sort of accomplice to the whole charade. And even when she'd asked to know more, he'd held back some of what he knew. He truly did believe it would be better for her to hear it from Rhea, regardless of the doubts he now had about his sister.

He recalled the look in her eyes when Rhea finally did tell her the truth. Though it wasn't directed entirely at him he could see how much it had pained her to learn the truth of her existence. That look had haunted him ever since.

It didn't matter what he wanted anymore; he truly didn't deserve her… Not before, and certainly not after today.

He reached down to brush a lock of moss green hair from her sleeping face and his heart fluttered. She was so lovely. Whether she was behind her desk going through the dozens of communications and reports they received, or in the midst of battle, covered in dust and blood - she was beautiful. But she couldn't be his…

He set her down gently, doing his best not to rouse her for she deserved her rest after today. Luckily it was a simple task for she was out cold. Getting to his feet he looked down at himself in disgust. The scales, talons, horns and wings were gone, his clothes were a mess and his body still ached all over.

He found the pile of his clothes that Byleth had recovered on her way to him and sighed. He'd never lost control before, not in all his long years on this earth. Not after Flayn had been injured, not after his wife had died… Even now he was not entirely certain what had changed to cause this. He hadn't even thought it possible for him to transform at all anymore and he would have been content to live out the remainder of his life without the ability to do so.

Seeing Rhea change had made him uneasy - not just her transformation into the Immaculate One, but her behavior in general. The long lives of the Nabatean people could be both a blessing and a curse. Even before the rise of the Agarthans, some of his kin fell to the illness he now believed was responsible for Rhea's bizarre and erratic behavior.

The thought that he may also be succumbing to it now just as they were on the brink of settling things once and for all… it set his teeth on edge. He needed to keep himself together, for Flayn for the church and for _her_. Even if he'd lost any hope of being more to her than just a friend or colleague.

Such lofty ambitions he'd had for the future… Determined to be someone Byleth could depend on, he'd called her family and asked for her trust. And then the moment she asked him to trust her he tried to push her away. He could say it was because he didn't want to harm her - a fear that was well founded. But in truth he didn't want her to see him like that. How could she ever trust him if he could lose control like this at a moments notice?

But the way she had looked at him, spoken to him. She was all gentleness and understanding - stubborn and unrelenting kindness.

"I don't deserve you." He whispered over her sleeping form before lifting her into his arms and turning to follow the path she had come to reach him.

He was surprised to find his own wyvern waiting in the clearing ahead of him. She regarded him with a look of irritation and impatience as he approached. "I'm sorry for keeping you waiting, my friend. Thank you for bringing her to me," he said, angling so he could give the wyvern a quick scratch under her chin. She responded with a disgruntled huff, but bowed her head, encouraging him to get on with it. She was likely tired of wasting time in the ravine and as anxious to get home as he was.

He braced Byleth in his arms and managed to get them both into the saddle without too much trouble and despite how sore the whole of him felt. They were in the air a moment later and on the short trip back Seteth's mind raced with how to proceed from here.

He couldn't exactly pretend as though nothing happened. However, he felt he needed to distance himself from her. He couldn't let his condition distract her from the battle that lay ahead of them. He'd harmed her enough already. But how to move forward? These feelings he harboured for her, could he really abandon them? Did he even need to?

She felt something too, regardless of what he tried to tell himself. Maybe when this was all over... He just needed to be patient. He would tell her when this was done, when they had time… He owed her that much at least…

* * *

Byleth woke alone in the infirmary and her heart sunk. She had thought…

"Ah, you're awake! Thank goodness!" Manuela exclaimed and rushed over to her bedside. "I wasn't that worried since you're always so resilient, but you had some pretty nasty cuts. It's a good thing Seteth managed to get you both back in one piece."

"Is he… alright then?" she asked, unable to keep the confusion and disorientation from her voice.

"Oh yes. A bit worn out, but he was fine as far as I could tell. You must have had quite the fight the two of you. Facing one of those beasts on your own. To think one would venture so close to the monastery," Manuela sighed.

"Yes…" He must have taken her back himself. Which meant he must have returned back to normal at some point. "I should get going," Byleth muttered as she got up.

Her arms and back were stiff and sore, but Manuela had bandaged her up nicely as she always did. "Just come back tomorrow so I can change those," Manuela instructed before sending Byleth on her way.

She wandered back to her room in a bit of a daze. She wasn't quite sure what she had expected upon their return to the monastery but waking up alone in the infirmary wasn't exactly it.

_I suppose he would want some space after that…_

She washed off and changed into a fresh set of clothes, and while that did improve her mood she still felt slightly off. As she left her room, she found herself headed back to the staff offices and right to Seteth's closed door.

She stood there for several moments just staring at the varnished wood, before finally knocking and letting herself in when she heard his call from the other side. "Ah, Professor, you're up."

She could tell he was doing his best to sound casual but judging by how his entire body went rigid at the sight of her she knew something was wrong.

"I just… wanted to check in and make sure you were alright. But I see you're already back at work, so I'll leave you alone."

She attempted to dart out of the room before he could respond but he'd somehow swept clear of his desk to cut her off before she could even open the door. "Byleth wait. I - I owe you my thanks for what you did."

"Not at all." She shook her head a little too violently, feeling the heat rise in her cheeks. Why had she let herself think what had happened yesterday would change anything?

"You risked your safety to help me. I was not certain I could come back from that, but you guided me through it."

"I knew you wouldn't hurt me. Not really, and not if you could help it." He frowned, clearly unhappy that she _had_ been hurt, even if her injuries were relatively minor. She looked away for a moment, curiosity niggling at the back of her mind. "Would you really have left without saying anything?"

"I -" He looked flustered, unable to meet her gaze. "If I had to. I would not risk the safety of Flayn, or you, or anyone here."

"I see." It was like they were chasing each other in circles. He was always so keen to be the pillar that held everyone up, but when he needed help, he kept her at arms length.

"Byleth, please understand. I still don't know why this happened and I don’t know if it will happen again. Until I can be certain that I am in control I must be on my guard."

"You could let me help you."

"You've done more than enough. And you have so many responsibilities already. I can manage for now. Just focus on the coming battle."

Byleth held back an exasperated sigh, but she couldn't keep from frowning. It was what she'd expected but she had still hoped… "Very well. Just know you can come to me if you need anything, Seteth. I'll leave you to your work then. You must have much to catch up on after yesterday."

* * *

For several moments after she left, he just stood there staring at the door. He felt like a fool. Everything he did and said seemed to have the opposite effect to what he intended. Even he couldn't miss the hurt in her eyes as she left.

He had to admit he was rather cold towards her, even for him, considering what they had just been through together. He could have accepted her offer, even if he didn't intend to take her up on it. He just didn't want to add any more to the burdens she already carried. She had the expectations of everyone on her shoulders, and an ancient evil to defeat. His problems, troubling and terrifying though they were, could wait.

He could hold out for just a little longer.

* * *

In the days before the battle he saw very little of Byleth beyond war councils and church services. She'd pass him in the halls, nod and smile politely, and then continue on her way. She still went out of her way to help him with some of his work where she could, but she seemed to have become far more adept at doing it whenever he wasn't around or without him realizing until she'd already come and gone.

He'd caught her working late on several occasions, reviewing the war table, rethinking their plan of attack. Most of the time she didn't even notice he was there, so wrapped up in whether their plans would see them to victory. In an unexpected reversal of roles, he found he was the one insisting she retire on those late nights, where in the past it had always been the opposite.

She had started to look worn down. Dark circles were a regular fixture beneath her eyes. Her skin had taken on a pallid complexion. More than one of their companions had noticed that she seemed to be forgetting to take meals.

"Brother, you have to talk to her." Flayn pleaded.

"Flayn, she's a grown woman. She can take care of herself."

"Well, brother, she clearly isn't, and everyone can see it. She's been different for quite a while in fact. I don't recall ever seeing her quite like this, not even after Jeralt died." She paused. "I am worried."

"I don't know that I am the right person to talk sense into her, Flayn." _Surely, I have done enough damage already_.

"Did something happen, brother? Ever since you both returned after disappearing that day things have seemed different between you." There was no accusation in her voice, only concern. And yet his daughter's uncanny ability to read the situation was setting him on edge.

"It complicated, Flayn."

"Does it have to be? She clearly cares very much for you, and you for her. And yet the way you interact with her I'm she sure has no idea."

"Flayn!"

"Father!" Seteth was immediately silenced. Flayn very rarely called him anything but "Brother" these days, even when they were alone. They couldn't risk giving themselves away, and it was better to keep up the habit. "I am not ignorant of how dangerous this coming battle is going to be. We may not all make it back…"

"I would not allow that. You will be safe; I will see to it."

"You know you can't promise that. No one can," she said gently, taking his hand in hers. "Don't you think it would be nice to spend some time with the one you care about before we face the enemy?"

"She has enough distractions, Flayn."

"You think you will be a distraction?" she asked incredulous.

He sighed, pinching the bridge of his nose. "There are things you don’t know, Flayn."

"Does she?"

"Yes."

"And yet whatever these things are they do not seem to have changed her feelings towards you," she insisted.

"You cannot know that."

"Neither can you, Father, until you talk to her." She released his hand and turned to leave. "I think you will regret it if you do not. Even we can only bide our time for so long."

He stood there for a few moments after she'd left, thinking he would be able to convince himself that she was just being overly dramatic. But he'd seen the effect of his cold words and inaction with his own eyes.

He left his office, crossing the short distance over to Byleth's and entered without knocking. She didn't even look up, sitting with her chin supported on the palm of her hand as she stared blankly into the mess of parchment on her desk.

"Um, Professor?"

She blinked blearily and looked up to him finally, a weary frown settling over her face as she saw him. "Oh, was there something you needed, Seteth?"

"I was just… checking in. You've been working late quite often lately. You should be getting your rest. We move out in a matter of days." He tried to keep the scolding tone from his voice, but even he knew it was so ingrained at this point, there was likely still a trace of it there.

"I'm well, Seteth. You needn't worry."

His eyes fell to a plate of food still sitting at the corner of her desk, untouched. Then the general state of disrepair her office was in. Parchment strewn about the floor; garments discarded on every available bit of furniture… It was as though she'd been sleeping here more often than her quarters. Byleth had never been the neatest person, but she'd never been quite this bad.

"Byleth is something wrong?"

"What do you mean?" Came her cold reply. She sounded almost as distant and emotionless as she had when she first arrived at Garreg Mach.

"You don’t eat, you hardly sleep. Have you been spending your nights in here?"

"There's too much to do, too much at stake. I have to make sure we're ready."

"You won't be in any state to face the enemy if you're running yourself into the ground," he pressed on. Now that he was looking for it, he could see how haggard she looked, and felt all the more the fool for not noticing sooner.

"I'm well, Seteth, and I can take care of myself. I've been doing so my whole life. You don’t need to lecture me or treat me like a child." There was an uncharacteristic hint of acid in her voice.

"That is not my intent. I simply worry for you."

"Well worry not. I'll be ready to face Nemesis when the time comes," she said trying to brush him off. She turned away from him, tucking a lock of hair behind her ear as she made as if to get back to her paperwork. And then he saw it. The tip of her ear was no longer rounded but pointed, like his own. When had that happened? "Was there anything else you needed?" she asked impatiently without looking up.

Snapping back to the present he fixed his eyes on her face. "Byleth, that day -"

"There is nothing more to discuss. You told me you needed space. I understand." He watched her body stiffen as she spoke. She would not make eye contact with him.

_I don’t need space, I need you._

The words were at the tip of his tongue, so desperate to come forth that he could almost taste them. But they remained unspoken. Instead he stood there speechless while she continued to stare at anything but him.

"If that is all, I have a few more things to do before I turn in."

"It can wait until tomorrow, surely." He couldn't keep the exasperation from his voice. She'd said _he_ was stubborn, but at times like this she often gave him a run for his money.

"Seteth, I really don’t need you hovering over me," she blurted, her voice raised as she abruptly got to her feet.

"That is _not_ my intent."

"Then what is this? I don't need an older brother fussing over me right now."

"That's not - wait what?" She thought he was treating her like Flayn or Rhea? But what else was she to think, how else had he ever treated her?

"I am grateful for everything you've done for me. For helping me discover who I really am. I'm - I'm glad you consider me family. But I can't - I don't want…" Her words broke off as she became more flustered. A flush started to dust her cheeks in a rosy hue. In the dim candlelight he could see a slight sheen of sweat on her brow.

He took a step towards her, thinking perhaps she might have a fever, but she backed away from him. "Byleth, I think you might be ill."

"I'm FINE."

He reached out without thinking and grabbed her by the wrist, felt her pulse racing a mile a minute. Her eyes flared as she attempted to yank her arm free, but he held fast. She actually snarled, baring sharply pointed canines at him. He was stunned into stillness for only a moment before he realized what was happening.

"Byleth, I think you're -"

"Just leave me!" She tried her wrench her arm free again, growling in frustration. Seteth watched as her fingernails started to sharpen and elongate to points, and bony little protrusions started appearing on her temples. "I don't need your help with this."

It shouldn't have taken having the situation reversed for him to realise how he had made her feel each time he'd rejected her help, but here he was. She was trembling slightly now, holding back what was happening to her with all her strength. "Please go, Seteth. It hurts too much."

"Let me take you to the infirmary then!" he insisted.

"Ugh! That's not what I mean!" Finally, she managed to pull free. She spun away from him retreating to the corner of the room furthest away from him and faced the wall, refusing to look at him.

"I can't bear you looking at me like that," she whispered so quietly he had to strain to hear her. "Like you care."

"But I do care!" Cautiously he started to move closer to her. If she noticed him approaching, she didn't react.

"I know… Because of what I am to the church, and because I'm like _family_." There was a distinct note of bitterness to her tone as she said "family".

Even now he couldn't believe what he was hearing. She couldn't possibly mean…

He continued to approach her slowly, afraid that any sudden movement would cause her to bolt as though she was some kind of wild animal. Even when he was a hair's breadth away, she didn't move, simply standing there, straining as she fought the changes afflicting her body. As gently as he could he placed his hand on her shoulder and was immediately rewarded with a shuddering sigh from her.

He felt something inside him respond to her reaction to his touch. Something wild and unrestrained and _feral_. He leaned in further, closing the distance between them, wrapping his free hand around her waist and relishing her reaction as she shuddered again while he pulled her against him. He buried his face in her neck, her scent enveloping him - jasmine and elderflower?

That day, when the feral creature had been trying to break free, it had wanted to sink its teeth into her soft flesh, to taste her and claim her, but he had resisted. It was rearing its head again now. He pressed his lips to her pulse, and she shivered, a small sound, not quite a sigh, coming forth like music to his ears.

"How may I show you how much I care for you, Byleth?" He whispered against her skin, sending a wave of gooseflesh down her neck.

"What?" she asked breathlessly. Her body was quickly becoming a furnace. They both were. Every place they touched was becoming fire.

"Tell me what I can do to prove to you what you mean to me?" Finally, she turned to face him. Though she still strained against her body's transformation, her expression was serious as she studied his face. It was as though she was expecting a trick. The feral thing was impatient, however. It wanted to act.

He leaned in, nipping at her lower lip before she could react. She froze, momentarily startled before her tongue darted out and brushed against his lips. A low, satisfied rumble came forth from deep in his throat, and he grinned against her lips. He kissed her in earnest now, practically devouring her lips. Hunger was taking over and he could feel his own body change as if in answer to the change occurring in her.

He braced his arms against the wall as claws jutted forth from his fingers, piercing the stone and sending bolts of pain up his arms. Whereas before the pain was unbearable, there was something different about this time. Something was calling out between them, blood to blood. Perhaps it had been there when he'd changed before, only now it was getting an answer.

Seteth watched as her eyes flashed again, her irises changing in shape, becoming almost reptilian. Byleth licked her lips hungrily as she watched horns appear at his temples, as he bared his teeth, now as sharp as hers. He brought one taloned hand down to stroke her cheek where white-gold scales were starting to emerge. "Tell me what you want of me," he urged her between kisses.

A low animal sound spilled from her lips as she took him by the collar, letting her claws rend the fabric as she pulled him even tighter against her. " _Everything_!" she purred as she tore his shirt open and buried her face in the nape of his neck.

She had always been bolder than he was, so he wasn't surprised when he felt her teeth pierce his skin, followed swiftly by her tongue soothing the little wound. His blood boiled in response. His arms looped around her, nails hooking into the back of her blouse and tugging down until he heard the satisfying sound of threads tearing. Humming with satisfaction he ran his hands over the scarred skin of her back, now slowly being covered by those lovely white-gold scales.

Seteth the man wanted to savour this - every touch, every sound, every shuddering breath. Seteth the beast wanted only to ravage her, bite and claim, bury himself inside her and fill her with his seed. Judging by her own voraciousness she was in a similar situation, pulling the shreds of her clothing away so she was pressed, skin to skin against his chest. The feel of her soft, full breasts against him nearly sent him into a frenzy.

He spun her around flattening her against the wall, his throbbing member pressed into the soft flesh of her ass. His fingers delved down beneath the seem of her pants, tugging them down so they pooled at her ankles. A sound somewhere between a giggle and squeal bubbled forth from her, and she wiggled her rear into his hips. His breath hitched as his cock pulsed in response.

Tugging his own trousers down he continued to rut against her ass, leaning in to whisper in her ear as he did. "Is this what you want, Byleth?" He asked, thrusting harder for emphasis.

She responded with a frustrated grunt, reaching back to tangle her fingers in his hair and angling so she could crush their lips together in another violent kiss before biting down on his lower lip. As they came away her own lips were stained with his blood. She licked it away with a wicked grin, goading him to respond in the way she wanted.

He could not deny her. He would never deny her again. Not now that he knew the truth about them both, the one he’d been too afraid to acknowledge.

After one final kiss, he plunged inside her, briefly relishing in how wet she already was for him, before the beast took over. He pumped into her relentlessly, losing himself bit by bit, piece by exquisite piece until there was only her and whatever joy, or relief he could bring her. With every sound she made, every twitch and spasm of her sex as she took him, he lost himself a little more.

Byleth pressed her face against the cold stone wall. Even in the haze of passion and primal abandon, she still tried to muffle the sounds coming forth from her lips. She keened as his hands slid up to tease her breasts, pinching her nipples until she was gasping his name. He felt the muscles of her sex tighten around him as she came undone. The sound of his name on her lip as she lost herself was the sweetest he'd ever heard.

As her body shuddered between him and the wall something started to protrude from her back. Seteth didn't know whether to pull away or remain with her as two pearlescent white wings came forth just below her shoulders, and a long elegant tail emerged just above her lovely pert ass. She groaned against the stone, the sound indecipherable from pain or pleasure. Seteth stilled. Even in this frenzy he needed to know if she was alright.

"Byleth?"

Another growl was his answer and then she pulled from him and spun, wings flexing out behind her. She was a sight to behold. He'd long given up on seeing another of his kind again. Yet here she was, in the flesh, in his arms…

"Mmmm," she purred, closing her eyes as he cupped her face delicately between clawed hands. "Mmm, m-more!" Her reptilian eyes fluttered open and her lips came crashing into his. Once again he was lost in her.

He hoisted her up, the weight of her new wings making the task slightly more difficult than it had been before, but neither of them really took much notice. Byleth locked her legs about Seteth's waist, grinding up against the length of him, almost causing him to lose his grip as the cloud of lust became honey-thick in his mind. He quickly walked them over to her desk, splaying her out over the scattered parchment. A second later he was plunging inside of her again, grinning down at her as she squealed with delight.

Byleth did not take her eyes from him once, watching him in all his half draconic glory as he took her mercilessly. Even when he froze for a moment, his spine going rigid as his own emerald wings and tail emerged, her gaze was locked on his eyes. Her own had become so dark they were almost black.

She coiled her tail around his thigh as he felt the pressure of her release build once more. Her breathing came in short, sharp pants. Her talons bit into his flesh, and her brow creased as she strained on the precipice of her climax. "Seteth, I -"

Her words were cut off as he leaned in, burying his face in the crook of her neck. As he sunk his teeth into her soft flesh she gasped, her whole body vibrating as she climaxed again for him. Seteth hummed, satisfied with the effect he was having on her - that they had on each other, before thrusting himself into her harder and faster than before.

Though her eyes were hazy, glazed over as the waves of ecstasy still rocked through her, they remained fixed on him. Emotions other than lust suddenly surged forth as he stared down at her - joy, fear, surprise…

"My love…" The words tumbled forth from his lips before he even realized he was speaking them.

Byleth's eyes widened in surprise, the glassy haze suddenly gone. An eternity of silence passed by in a matter of seconds until Byleth reached up to gently draw his face down to hers, kissing him softly, almost chastely. For a moment they simply held each other, drinking in each other's warmth and touch. Tenderness soon melted into heat, however, stoked by his unwitting revelation.

His hips began to thrust forward once more, and their kiss was broken up between panted breaths, then cries of pleasure. The beast took over again, plunging home with abandon, locking his lips on the sensitive peaks of her beasts, rumbling out satisfied growls as she came apart piece by piece beneath him.

When he finally found his own release, she came along with him, quivering one last time as he spilled his seed inside her. As the shockwaves of their orgasms rocked through the both of them, Byleth smiled up at him lazily. She reached her hand up to trace the line of his jaw with a clawed fingertip before tangling her fingers in his hair. " _Mine_ ," she said dreamily. " _My_ love."

She sighed, closing her eyes as she continued to trace lazy patterns along his jaw, down his neck, and across his chest. Seteth hardly noticed, still in shock after hearing what she'd just confessed.

"Byleth are you… Are you well?" he asked hesitantly.

"Oh, yes," she replied with another sigh. Her eyes remained closed and she appeared to already be drifting to sleep.

The scales and horns remained, but her wings and tail were already receding. His own form seemed to be returning to normal much quicker than hers. As Seteth pulled himself free of her, tucking himself back into his trousers, he looked desperately about the small office for cloaks or blankets to replace their garments. Both their clothes were quite ruined, but his personal quarters were not far, and it was extremely late. He should be able to get them both there without anyone taking notice…

He spotted her cloak hanging by the door, and a woolen blanket slung over the back of her chair. As he started for her cloak, she made a disgruntled sound, but didn't open her eyes as she blindly reached for him. "Just a moment, dear one," he said, pressing a kiss to her brow.

He retrieved her cloak quickly and wrapped it as securely as he could about her mostly naked form. She hardly even stirred, but for the soft sounds she made whenever his hands made contact with her skin. He then wrapped the blanket around his own nakedness before taking her up into his arms and heading for the door.

The corridor was blessedly silent, empty, and very dark as he peaked out. With a deep breath he left Byleth's office behind and sped down the halls as quietly as possible, keeping his eyes out for any patrolling guards or stray night owls lurking in the halls. He did not relax again until he'd shut the door to his quarters behind him and bolted the door.

As he set Byleth down on his bed he wondered how she'd react to waking up with him the coming morning. Part of him was still worried that what had just transpired between them was the result of their transformations. That any confessions she had made were under the haze of lust and primal urges which lowered their inhibitions, even though he knew his own confession was true to his own heart.

"My love." He repeated the words again without thinking as he brushed a few stray strands of moss green hair from her brow. She leaned into his touch and he thought his heart would burst out of his chest.

Shedding what remained of his tattered clothing he climbed into bed with her, wrapping his arm around her waist and pulling her close. Even if it was just for tonight, he would savour this. If everything were to change back to the way things were come morning at least he could have just this one thing… But he prayed this was not the end for them.

* * *

Byleth woke to the sound of someone breathing softly just over her shoulder. Then she took notice of the arm draped around her, the unfamiliar bed and room…

Then it all came back to her.

She and Seteth changing into beasts before each others’ eyes. And then… _Oh, Goddess…_

She looked down at the arm that encircled her, fingers laced with hers, unmistakeable green hair dusting the forearm. Did he remember? It had all been such a frenzy she could hardly keep her memory straight herself, but she recalled enough… Enough to remember the way he'd looked at her, the way he'd kissed her, the things he'd said - he'd meant them… hadn't he?

She didn't want to rouse him, but she wanted to look at him. If this was the last time she could be held in his arms, to see his face as he slept peacefully, she wanted to savour it. So, carefully she turned with his arm still draped over her so that she was staring into his broad chest. Seteth grumbled a little at the disturbance but didn't wake.

He had claw marks from his collarbone down to his sternum that didn't look too dissimilar to the ones he'd left on her arms and back. She traced her fingers over the pale scar tissue, already mostly healed. As she looked up at his sleeping face, she thought she felt her heart flutter to life - just for a moment. Something surely stirred within her, making her chest tight, her pulse race and her cheeks flushed with heat.

How could she ever let him go now? This was all too good to be true, certainly. He would wake and come to his senses just as he had after that day in the ravine. He didn't want her. How could he? She wasn't like him, and she still carried her mother's unbeating heart within her breast, the surest sign that she wasn’t normal. She may look like him, and could even change into a scaled, draconic creature like him, but she was not truly a Nabatean as he was. Byleth wasn't even certain she could be considered human. She was unnatural.

"Why do you weep, dear one?" His voice hit her suddenly, though it was soft and so gentle.

She hadn't noticed the tears and was shocked herself to find her cheeks stained with saltwater. She had not wept since her father…

"Byleth?" he continued.

"I'm sorry. I'm sorry for - for everything!" she stammered.

"You've nothing to be sorry for."

"I lost control."

"You maintained your composure far better than I, all things considered. You didn’t flee." He was being so kind. But she couldn't trust it. There had been times in the past when she'd thought the things he'd said and done meant something more. But every time they would return to the way things were. Always maintaining their distance. Never to be anything more than a professor and an advisor.

"You didn't have to… do what you did," she muttered.

"I wanted to." He tilted her chin up so she could meet his eyes finally. "Because I love you, Byleth."

She blinked up at him in disbelief. She knew what he'd said last night, and though he said it again now she was still having a difficult time believing it. Her mouth moved but no words would come out.

"Have I made it so difficult for you to believe me when I say it?" he said sounding disheartened.

"No! It's just," she protested, searching for what to say. "You've kept me at arms length for so long, Seteth."

"Would you accept my poor excuse, which is that I've simply been a fool? That I thought I would only be a burden to you? For a while I thought it was impossible for someone as extraordinary as you to want someone like me?" His hand slid up from her chin to stroke her cheek, wiping away the tears. "I had planned to tell you, though. After Nemesis, when there were fewer distractions."

"Someone like - You thought _you_ were undeserving of _me_? But I'm just - "

"Perfect," he sighed, leaning his forehead against hers before pressing his lips to her own. All her confusion and protests died on her tongue as he kissed her, his arms pulling her in tight. It was then that she realized there was nothing separating them beneath the covers, and heat rapidly began to flood her cheeks.

It was a momentary thought and it passed quickly, for she found she quite liked the feel of his skin against hers. If there was any remaining doubt in her mind that he desired her it was dashed completely in that instant. The kiss would have been enough, but she could feel him becoming hard where their hips were pressed together. Instinctually her leg came up to wrap around his waist and he groaned against her mouth.

"I do love you, Byleth," he breathed as he pulled away from her lips with a gasp. "Whatever you ask of me, I will do it."

She looked up at him silently, drinking in everything about this moment. Reaching up she cupped his cheek with one hand, and he turned to press a kiss to her palm. The small gesture sent another trill through her veins. "I don’t need anything, Seteth. Just you. Just this."

His lips came down to meet hers again and she almost lost herself again completely, the sensation so deliciously sweet. But she needed to tell him, to say the words aloud. "Seteth," she panted. "I love you; you know that?"

He chuckled and it was such a wonderful sound. "Yes. It took me some time to accept both my own feelings as well as yours, but finally I see what has been right before me for some time."

A laugh of her own escaped her lips. "Good, then." She looped her arms around his neck and pulled him back down so she could kiss him once more. She could kiss this man forever if given the chance. But as his hands started to explore the curves of her body, she thought of several other things she could do forever with him that would be just as lovely.

But as his hand was sliding up the sensitive flesh of her inner thigh a frantic knock came at the door. He groaned into the crook of her neck and she couldn’t help but chuckle softly. "Perhaps they'll go away?" she said though she didn't have much hope.

"It's quite late," he sighed, but didn't release her. "Later than is customary for either of us at any rate."

As if on cue, the knocking returned, slightly more urgent than before. "Brother? Are you in there?"

Seteth looked more frustrated than she would have expected. Did he truly want her that badly? Perhaps seeing his control slip around her was something she would need to become accustomed to. The thought made her grin even wider.

"I am, Flayn. What is it?" he called back to her, still apparently unwilling to leave Byleth just yet.

"Oh!" came the shocked reply. "It's nearly noon and we hadn't seen any sign of you or the professor. And when I checked her office it was in quite a state. It appeared as though someone loosed a wild animal in there."

The urge to tease him grew as she watched him struggle to decide how to handle this situation. She trailed kisses along his jaw and down his neck, soothed her fingers through his hair and over his scalp. She delighted when she heard the hitch in his breath, when he fisted his hands in the sheets.

"Byleth…" he breathed through clenched teeth.

"Yes, my love?"

A familiar growl rumbled from deep in his throat as he took both her hands and pinned them over her head. Clearly something of the beast was still there lurking beneath the surface. "You are a wicked creature," he hissed before claiming her mouth with his.

In that moment she didn't care if Flayn, or the entire monastery for that matter, listened at the door, she wanted to have him inside her _now_. With her arms still pinned to the mattress, she hooked both her legs around his waist and watched as he hissed out a strained breath, even as his hips bucked into hers. "I may be a wicked creature, but I am _your_ wicked creature."

"You…"

"Brother?"

Seteth collapsed, releasing her arms and smothering his face into Byleth's shoulder. "You will be the death of me, my wicked love," he said against her neck.

"Never that I hope," she said pressing a kiss to his temple.

After one last kiss he drew himself away and started rummaging through his wardrobe for something to wear. "Just a moment, Flayn!" he called as he pulled on a shirt and trousers, then made his way to the door.

Byleth burrowed under the covers as much as was possible. She didn't think she could be seen from the doorway, providing he didn't open it fully, but she couldn't be sure. She sat back and listened with interest. While she was still enjoying seeing Seteth squirm just a little, she didn't want to startle Flayn.

"Brother, is everything alright?" She heard Flayn ask as Seteth cracked the door open.

"Yes, quite alright."

"But the professor-"

"She's here, Flayn." Byleth could hear the tension in his voice, taught as a bowstring. She was surprised he went straight to admitting she was there. "You were right, she was quite exhausted. I brought her here to rest for the night as it was closer than her own quarters. She is still sleeping."

"Oh… But her office-"

"I will ask her about it when she wakes," he said hurriedly. "Would you be so kind as to make her excuses to the rest of the war counsel? I'm sure she'll be up any moment now. And if you could have someone bring her things…"

"Her things?"

"She slept in her clothes."

"Oh! Of course. But… are you sure you're well? You look rather worn out yourself today."

"Yes, yes, please do not worry for me."

"Very well." Flayn sounded skeptical. "I'll have her things brought up shortly."

"Thank you." He sounded sincere, as well as relieved. Byleth couldn't keep from grinning as he closed the door once more and returned her.

He gave her an incredulous look as he climbed back into bed. "Lying to your daughter's face already?" she asked with a sly smile.

"What would you have done, may I ask?"

"I suppose we may never know," she teased.

He stalked over to her on hands and knees until he was looming over her, a predatory glint in his eyes. "That is a very weak response, Professor." He pulled the covers away and let his eyes roam over her naked form. Even after everything that had already passed between them, she flushed beneath the heat of his wandering gaze.

Byleth hooked her legs around his waist once more while looping her arms around his neck. "Nothing to say for yourself then?" he asked, pulling her up into his arms. But Byleth just continued to grin and remained silent as she doused his neck in kisses while her hands went to the ties of his trousers. "You are insatiable."

"Well, I feel as though I've been denied for some time." She made a satisfied sound as her hands pulled his engorged length free.

"Flayn will return soon," he hissed.

"Then we'd best be quick, my love." Seteth didn't say another word. He simply raised her up by her hips before lowering her back down and impaling her on his cock. She let out a gleeful sigh as she started to move over him, matching his pace as he thrust up into her. They were both wound up tighter than either of them had truly realized and it didn't take long for them both to come undone.

Seteth held her over him as they came down from their high, and she was content to have him inside her for a little longer. Very soon they would have to return to war counsels, battalion formations, provisioning, and then in just a few days, the battle itself. If only they both hadn't been so stubborn before now.

"We shall have more time," he whispered in her ear.

"Can you read my mind now?" she asked without drawing away.

"I do not need to. I think we feel the same, you and I, but we will come through this… together." He drew away just enough to cup her face with his palm.

Byleth smiled, tilting forward to rest her forehead against his. "Together."

* * *

In the days that followed their victory against Nemesis, Byleth, Seteth and their allies had much to rebuild. Seteth had insisted they keep their relationship between themselves and just their closest allies so that the people of Fódlan could focus on rebuilding. Their new roles of Queen and Prime Minister meant they themselves had very little time for personal matters in the months immediately following Nemesis's defeat.

Still, they were able to find moments where they could steal away and leave their new responsibilities behind, even if only for a little while. During those times they learned together what their Nabatean blood was capable of, how to control their draconic forms, and discovered a new sense of freedom as they grew more comfortable with their more primal sides.

After they did eventually achieve stability for Fódlan, years after the final battle on the Caledonian Plateau, they announced their marriage. It was a small occasion, despite their esteemed positions, but they both preferred a more modest affair. Still, when they announced it to their subjects there was much rejoicing.

They led Fódlan together for many years with a firm but nurturing hand, until eventually it came time to hand the responsibility of governing Fódlan off to the people. They could only guide them for so long, and neither of them wanted to repeat the mistakes that Rhea had made, well intentioned though she may have been. And though Seteth may never have admitted it, they both deserved to rest after everything they had done, and a particularly long life of diligently waiting and watching on his part.

Byleth was a great help in easing him into a more relaxed and peaceful life. She even helped him to finally let go of his fear of allowing Flayn to live a life of her own without having to constantly hover over her. They ended up settling in a secluded, forested place not far from the monastery where Flayn would come visit them from time to time, paying her respects to her parents and eventually to visit her new younger siblings.

They would never stop watching over the land they had fought and bled for over so many years. But finally, at long last they achieved peace not just for Fódlan, but for themselves.


End file.
